Carbon-containing materials, e.g., coal, lignin waste materials, and rubber tire pellets, are used as solid fuel. They contain different amounts of carbon, sulfur, moisture, and volatile components, thereby generating various heat values and pollutants when burned.
In particular, coal, a naturally occurring carbon-containing material widely used in industry as a fuel source, is classified as peat, lignite, sub-bituminous coal, bituminous coal, or anthracite, each class having a quality from low to high. Untreated coal produces low heat values and high levels of air pollution after ignition. Thus, treatments during coal preparation, such as coal grinding, coal sieving, coal washing, coal drying, and coal mixing, are generally performed to increase heat values and lower levels of air pollution.
Conventional methods, aiming at enhancing the heat values of carbon-containing materials, encounter several major issues, e.g., operation at high pressures or temperatures and use of a complex system, which lead to high cost and low efficiency.
There is a need to develop a new method for enhancing the carbon contents of carbon-containing materials, thereby increasing their heat values.